Explanation:
Is only one black hole spewing high energy radiation -- or two?
To
help find out,
astronomers trained
NASA's Earth-orbiting
NuSTAR and
Chandra
telescopes on
Arp 299, the enigmatic colliding galaxies expelling the radiation.
The two galaxies of Arp 299 have been locked in a
gravitational combat for millions of years,
while their central black holes will soon
do battle themselves.
Featured, the high-resolution visible-light image was taken by
Hubble, while the superposed diffuse glow of
X-ray light
was imaged by NuSTAR and shown in false-colour red, green, and blue.
NuSTAR
observations show that only one of the
central black holes is seen fighting its way through a region of gas and dust -- and so absorbing matter and emitting X-rays.
The energetic radiation, coming only from the galaxy centre on the right, is surely
created nearby -- but
outside -- the central
black hole's
event horizon.
In a billion years or so, only one
composite galaxy will remain, and only one
central supermassive black hole.
Soon thereafter, though, another galaxy may enter the fray.